We can often see that because of the leakage of the exterior wall, many buildings have become flowery cats, and the exterior wall finishing layer is peeling, the indoor moisture returns, and the wall leakage water makes many owners miserable. Not to mention the high cost of maintenance, the risk factor of maintenance is higher, and the effect of maintenance is difficult to guarantee.
For a long time, the waterproofing of building exterior walls has not received enough attention, and only the "Technical Regulations for Building Exterior Wall Waterproofing Engineering" JGJ T 235-2011 edited by the National Academy of Building Research can be used as a reference. The state has not issued corresponding technical standards, so the waterproofing of building exterior walls is varied, and most of them are not even waterproofed. In March 2017, the Shenzhen Waterproof Industry Association led the compilation of the "Building Exterior Wall Waterproofing and Leakage Control Technology", which proposed the corresponding method for the leakage of the building exterior wall.
1. Exterior wall waterproofing includes the overall waterproofing of the wall and the waterproofing of the node structure
Exterior wall waterproofing should have the basic function of blocking rain and snow water from invading the wall, and should have the properties of freeze-thaw resistance, high and low temperature resistance, and wind load.
Exterior wall waterproofing is generally divided into exterior wall overall waterproofing and node structure waterproofing, exterior wall overall waterproofing we all know, node structure waterproofing is to use a structural form to block the passage of water and prevent water from invading the interior, common measures are parapet wall, balcony, doors and windows, wall construction, exterior wall separation joints, deformation joint waterproofing, etc.
Second, the selection of exterior wall waterproof materials
The use of waterproof materials for exterior wall waterproofing is a special measure taken for projects in rainy areas or where it is necessary to carry out exterior wall waterproofing. Use waterproof materials to block the passage of water or slow down the rate of rainwater infiltration, and waterproof or enhance the ability to resist seepage.
Exterior wall waterproofing materials are generally divided into: rigid waterproofing materials, flexible waterproofing materials, hydrophobic materials, sealing materials and waterproof and breathable membranes. Rigid materials include various types of waterproof mortar, polymer cement waterproof slurry; Flexible waterproof materials are mainly polyurethane waterproof coatings, polymer emulsion waterproof coatings, etc.
3. How to do the waterproofing of the external wall in the leakage part of the external wall?
1. According to the actual situation of the site, clean up the original exterior wall paint of the waterproof part of the base, especially the broken and loose parts of the base to completely clean up the hard foundation.
2. Clean the coating, dust, oil stains and stains on the surface of the waterproof base layer to make the waterproof material firmly bonded.
3. On the basis of clean base treatment, diluted with high-grade "Shengqiang" brand silicone waterproof coating and water at a ratio of 1:2, mixed with high-grade cement to make plaster, and detailed treatment of trachoma, honeycomb and cracking.
4. When repairing irregular cracks, the cracks exceeding 2mm should be repaired with filament non-woven fabrics and special coatings for silicone exterior walls to prevent the cracks from continuing to expand.
5. Strengthen the treatment of important parts such as the perimeter of the window, the bottom of the eaves, the embedded parts, and the wall pipe.
6. After the base layer to be repaired is treated and dried, the project parts are painted with high-grade "Shengqiang" brand environmentally friendly silicone special waterproof coating for interior and exterior walls according to the standard.
7. The waterproof coating should be stirred evenly before construction.
8. The paint is constructed by brushing method, and the direction and length of the stroke should be consistent, and the brushing should be uniform and should not be missed.
9. During the mechanical spraying construction, the spraying should be uniform, the stubble should be pressed in place, and the spraying should not be leaked, so that the surface is smooth.
10. Clean up the site after the construction is completed.
Exterior insulation exterior walls:
1.When coating or block finishes are used, the waterproof layer should be located between the insulation layer and the wall base layer, and the waterproof layer can be polymer cement waterproof mortar or ordinary waterproof mortar;
2.The mortar waterproof layer can be reinforced with alkali-resistant glass fiber mesh cloth, and it is appropriate to fix it in the structural wall with anchor bolts;
3.The mortar waterproof layer should be left with separation joints, and the separation joints should be set at the junction of different materials of the wall structure. The horizontal separator should be flush with the upper or lower edge of the window; The spacing of vertical separators should not be greater than 600m, it should be aligned with the sides of the door and window frame. The width of the separator should be 8-10mm, and the sealing material should be used in the seam for sealing treatment;
4.If there is a basement, the waterproof layer of the external wall should be overlapped with the waterproof layer of the basement;
5.The minimum thickness of the waterproofing layer shall be in accordance with the provisions of the table:
Fourth, the node structure is waterproof
1.The waterproof design of the exterior wall node structure of the building should include the waterproof design of the joint parts such as door and window openings, canopies, balconies, deformation joints, pipes extending out of the exterior wall, parapet wall roofing, external wall embedded parts, and prefabricated components.
2.The waterproof layer of the external wall of the building should be set on the waterfront surface.
3.The junction of different materials should be made of alkali-resistant glass fiber mesh cloth of not less than 150mm on each side for crack resistance reinforcement.
4.The waterproof layer of the exterior wall should be extended to the door and window frame, and the waterproof layer and the door and window frame should be reserved with grooves and filled with sealing materials; The gap between the door and window frame and the wall should be filled with polymer cement mortar or foamed polyurethane; The outer mouth of the frieze on the door and window should be made of drip line; The external window sill should be set with an external drainage slope of not less than 5%.
5.The awning should be set with an external drainage slope of not less than 1%, and the lower edge of the outer mouth should be made a drip line; The waterproof layer at the junction of the canopy and the external wall should be continuous; The waterproof layer of the canopy should be extended to the outer mouth and turned down to the drip line;
6.The balcony should be set with a drainage slope of not less than 1% to the water outlet, and the surrounding area of the water outlet should be filled with sealing materials; The lower edge of the outer mouth of the balcony should be made a drip line.
7.The pipe through the outer wall should be casing, the casing should be high inside and low outside, the slope should not be less than 5%, and the perimeter of the casing should be waterproof and sealed.
8.The top of the parapet wall is made of cast-in-place reinforced concrete, and the top should be sloped inward, with a slope of not less than 2%; When concrete is used for roofing, the waterproofing layer of the exterior wall should extend to the drip line on the inside of the roof.
9.The perimeter of the embedded parts of the outer wall should be closed tightly with sealing materials, and the sealing materials and waterproof layers should be continuous.